This present invention generally pertains to modular electrical connector systems that comprise a receptacle connector assembly and a plug connector assembly for connecting AC and DC power and electrical signals by overall arrangements that include wire-to-board, board-to-board, coplanar and right angle connections. The modular connectors, advantageously exhibiting minimum height and width dimensions, can transmit multiple power supplies, while having the capability to easily connect and disconnect the connector assembly from the power input module.